|
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] RE: iSCSI Naming and DiscoveryJulian, that is exactly what is happening. . . . John L. Hufferd Senior Technical Staff Member (STSM) IBM/SSG San Jose Ca (408) 256-0403, Tie: 276-0403 Internet address: hufferd@us.ibm.com julian_satran@il.ibm.com@ece.cmu.edu on 10/06/2000 10:14:22 AM Sent by: owner-ips@ece.cmu.edu To: ips@ece.cmu.edu cc: Subject: RE: iSCSI Naming and Discovery Well I'll try to be more explicit and answers Rod's note: Given that an FC gateway is FCP aware it can issue the relevant queries and cache results to avoid the query penalty at ever access. However I think that even this is excessive unless somebody intends to build virtual control units composed of a multidude of controllers beyond a gateway. Julo "DeKoning, Rod" <rdekonin@lsil.com> on 06/10/2000 17:09:53 Please respond to "DeKoning, Rod" <rdekonin@lsil.com> To: Julian Satran/Haifa/IBM@IBMIL, ips@ece.cmu.edu cc: Subject: RE: iSCSI Naming and Discovery Please keep in mind that the Logical Unit Number (LUN) is nothing more than a handle that means nothing without the context of the Initiator/Target. SCSI defines a nexus as a combination of the Initiator - Target - LUN. This nexus defines a path to a Logical Unit. The recently introduced Access Control mechanisms are designed to allow a host to provide several features, including: 1. The ability to map the same LUN to multiple Logical Units within a target to respective different hosts. 2. The ability to map the same Logical Unit to multiple LUNs within a target to respective different hosts. These mechanisms imply that the LUN identifier must be taken within the context of the INQUIRY VPD Page 83 volume WWN. Regards Rod DeKoning Manager Storage Solutions Architecture LSI Logic Storage Systems Inc. ph:316-636-8842 fax:x8889 rod.dekoning@lsil.com -----Original Message----- From: julian_satran@il.ibm.com [mailto:julian_satran@il.ibm.com] Sent: Friday, October 06, 2000 3:47 AM To: ips@ece.cmu.edu Subject: RE: iSCSI Naming and Discovery Joshua & John, If the troublesome item is for a "knowledgeable" gateway to to FC to get a hold on LUNs then this can be done within the current draft. The LUN in the PDUs is an 8byte "object" opaque to iSCSI. An initiator can choose to put there a WWN to be replaced (rewritten) by the gateway with a LUN or nay such commbination. This operation is stateless. Julo "Joshua Tseng/Nishan Systems" <joshua.tseng@NishanSystems.com> on 05/10/2000 22:26:01 Please respond to "Joshua Tseng/Nishan Systems" <joshua.tseng@NishanSystems.com> To: ips@ece.cmu.edu cc: (bcc: Julian Satran/Haifa/IBM) Subject: RE: iSCSI Naming and Discovery John, >Joshua, >I think the LU being part of the "/Modifier" is a bit problematical. You >should focus on the connections each end, and let the LU stuff be >transparent to your Gateway. They will of course use Report LUNs and >Inquiry and use their approprate LU number, I am having problems >understanding why a gateway would need to know the LU number. > >Could you resend your note without the LUN stuff so that we can see, a >little easier, what you think is really needed. You are right...my bad. The LUN is carried in the iSCSI PDU. What is needed in the Fibre Channel World Wide Port Name (WWPN), which the gateway will need in order to address the Fibre Channel device. The gateway/proxy should register this attribute key in the name server (yes Doug--an LDAP-based server) for retrieval by the iSCSI initiator, who can use it in the /modifier when addressing the Fibre Channel target. Josh - att1.htm
Home Last updated: Tue Sep 04 01:06:47 2001 6315 messages in chronological order |